As the largest cause of morbidity and mortality in this country, acute cardiac ischemia (ACI: which includes acute myocardial infarction [AMI] and unstable angina pectoris [UAP], which can lead to AMI) is the most common serious condition requiring emergency and acute care. Among the 7 million patients who present to emergency departments (EDs) in this country each year with symptoms consistent with ACI, errors are made both in ED triage and treatment. In ED triage, in this country each year, approximately 12,000 patients with AMI and 14,000 with UAP are mistakenly sent home, which nearly doubles the expected mortality rates for these patients and contributes to the status of missed ACI in the ED as the largest cost category of adult malpractice claims in the US. In ED treatment, although for ED patients with AMI, the lifesaving impact of thrombolytic therapy is directly related to the earliness of its use, many are not treated promptly, and about 90,000 per year are not treated at all. These errors in triage and treatment for ACI are clinically critical to the patient and occur on a scale that makes them public health issue, and thus present important opportunities to reduce medical errors. This project aims to reduce medical errors in ED triage and treatment for ACI based on a time-insensitive predictive instrument information system (TIPI-IS), designed to be attractive to all members of the health care system, by providing real-time, concurrent, and retrospective decision support. This approach rests on TIPI-capable electrocardiograph's ability to compute, for every ED patient upon presentation, a 0-100% probability that a patient truly has ACI, and if having an AMI, the likely outcome benefits of thrombolytic therapy. This project will consist of a before-after time- series design to measure the impact of the intervention with stepwise implementation. In Phase 1 the system will be fully implemented at New England Medical Center (NEMC) and revisions made to promote user- friendliness at all levels. In Phase 2, the system will be used in the three main hospitals in the Lifespan System. In Phase 3, Marsh USA will partner with us to distribute this system to its insured hospitals and managed care organizations. This plan thus allows demonstration of the usefulness of the TIPI-IS as an error reduction system, first in a single hospital, then for a group of hospitals, and then in a sample of health care systems nationally.